The subject matter disclosed herein relates to collision prediction and avoidance in aircraft, such as an unmanned aerial systems or a manned craft flying with a reduced crew.
Unmanned aerial systems (UASs) are systems that include an aerial vehicle that can be piloted from the ground (i.e., remotely) and/or that fly more or less autonomously (i.e., without direct human control or oversight). The UAS may also consist of a ground control station and one or several such aircraft that communicate with and are controlled by the ground control station. The airborne component of such systems can range in size from grams to tons and are set to become more prevalent in the aerospace domain. Civilian uses may include such functions as agricultural crop spraying, electrical power line checking, atmospheric research, data-link relay, and traffic/security surveillance.
Removing the pilot provides the UAS platform designer with additional freedom in terms of maneuver performance, size, payload and endurance constraints when compared with manned aircraft. Further, UASs are generally considered to offer benefits both in survivability and expendability, as well as being cost effective. Thus, UASs offer the opportunity to perform high risk, dangerous and monotonous missions autonomously or with substantially reduced manpower.
However, despite these benefits, there are several challenges concerning the operation and integration of UASs into regulated or commercial airspace; these include safety and reliability, as well as cost and regulations. One safety challenge facing UASs is the ability to sense and detect other airborne craft, thereby avoiding mid-air collisions. Conceptually, collision avoidance can be divided into separation assurance and collision avoidance. Separation management is usually achieved through procedural rules and air traffic control instructions. Collision avoidance is needed in cases of inadequate separation. Collision avoidance may rely, traditionally, on a pilot's ability to “see and avoid” and may also rely on cooperative technologies such as Traffic Collision Avoidance System (TCAS), and Automatic Dependent Surveillance-Broadcast (ADS-B). However, UAS can not depend exclusively on TCAS and ADS-B systems, since there will be airspace users that are not equipped with these systems (i.e., are not cooperative). Therefore, there is a need for systems and/or measures that would allow a UAS to maintain adequate separation from other airborne craft and to implement avoidance measures when adequate separation is lost.